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| In situ remediation of U-and Cd-contaminated soils by immobilized microorganisms and biochar |
| Received:February 24, 2018 |
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| KeyWord:U and Cd contamination;biochar;immobilized microorganism;extractable fractions |
| Author Name | Affiliation | E-mail | | QI Xin | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China | | | CHEN Xiao-ming | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
Defense Key Laboratory, Southwest University of Science and Technology, Mianyang 621010, China | chenxiaoming@swust.edu.cn | | XIAO Shi-qi | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China | | | ZHANG Xiang-hui | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China | | | TIAN Jia | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China | | | GOU Jia-lei | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China | | | ZHUO Chi-fu | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China | | | LUO Xue-gang | College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China | |
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| Abstract: |
| The objectives of the current study are to investigate the effects of immobilized microorganism technology on passivation of uranium(U)and cadmium(Cd). For these effects, this study screened the mixture of certain proportions of three bacteria on U and Cd for high removal efficiency. In addition, three kinds of passivators, including(ⅰ)biochar,(ⅱ)bacterial mixture adsorbed fixation by biochar, and (ⅲ)embedded fixation with sodium alginate after biochar adsorption, were applied to assess the effects on soil physicochemical properties and extractable U and Cd. The results showed that U and Cd were effectively removed from aqueous solutions by four kinds of bacterial mixtures; particularly, a mixture of equal amounts of Bacillus subtilis, Citrobacter, and Bacillus cereus resulted in the best removal rate. Soil pH increased after passivation treatments. Moreover, with an increase in the amount of the passivator applied, the soil pH increased. Soil cation exchange capacity and organic matter content increased in the passivation treatments. In addition, soil cation exchange capacity was highest in the biochar treatment than that in other treatments. Soil organic matter content was significantly higher for the biochar treatment and adsorption fixation treatment than that in the embedding fixation treatment. Extractable U and Cd content in soils showed a steady decrease with an increase in passivation time in the passivation treatments. The effects were significantly different when the different passivation treatments were used, and they could be ordered as follows:Adsorption fixation treatment > biochar treatment > embedding fixation treatment;moreover, as the amount of passivator increased, the passivation effects increased. The results show that the immobilized microorganism technology has potential applications in the remediation of heavy metal pollutants present in soil. |
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